﻿using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace MySoft.Security
{
    /// <summary> 
    /// DES加密
    /// </summary> 
    public static class DES
    {
        //默认密钥向量
        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };


        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <param name="encryptKey">加密密钥,要求为8位</param>
        /// <returns>加密成功返回加密后的字符串,失败返回源串</returns>
        public static string Encrypt(string encryptString, string encryptKey)
        {
            encryptKey = CoreHelper.GetSubString(encryptKey, 8, "");
            encryptKey = encryptKey.PadRight(8, ' ');
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

            DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
            using (MemoryStream mStream = new MemoryStream())
            using (CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write))
            {
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串,失败返源串</returns>
        public static string Decrypt(string decryptString, string decryptKey)
        {
            decryptKey = CoreHelper.GetSubString(decryptKey, 8, "");
            decryptKey = decryptKey.PadRight(8, ' ');
            byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Convert.FromBase64String(decryptString);

            DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
            using (MemoryStream mStream = new MemoryStream())
            using (CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write))
            {
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
        }

        #region DES加密解密


        /// DES加密
        /// <param >待加密的字符串</param>
        /// <param >加密密钥,要求为8位</param>
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
        public static byte[] Encrypt(byte[] data, byte[] iv, string encryptKey)
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
            byte[] rgbIV = iv;
            byte[] inputByteArray = data;

            DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
            using (MemoryStream mStream = new MemoryStream())
            using (CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write))
            {
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();

                return mStream.ToArray();
            }
        }

        /// DES解密
        /// <param >待解密的字符串</param>
        /// <param >解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>      
        public static byte[] Decrypt(byte[] data, byte[] iv, string decryptKey)
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0, 8));
            byte[] rgbIV = iv;
            byte[] inputByteArray = data;

            DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
            using (MemoryStream mStream = new MemoryStream())
            using (CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write))
            {
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();

                return mStream.ToArray();
            }
        }

        #endregion
    }
}
